Insect-borne diseases such as malaria continue to devastate a large fraction of the world's population. Transposable element-based transgenic technology has been proposed as a means by which insect vector-borne diseases might be controlled. Indeed, this idea has stimulated an enormous amount of research in the area of mosquito molecular genetics and transposable element biology leading to the development of functional germline transformation vectors and the creation of mosquitoes with genetically engineered refractory phenotypes. Progress has been such that questions of when, where and how this technology can be brought out of the laboratory and applied to problems such as Anopheles gambiae-transmitted malaria in Africa are being considered. The behavior and characteristics of actively transposing insect gene vectors in Anopheles gambiae populations remains a significant unknown. The long range goals of this project ("hobo -like elements in insects") remain to i) understand the basic biochemistry, genetics and evolution of transposable element movement and regulation, ii) develop transposable elements into gene vectors for nondrosophilid insects, and iii) deploy this technology against human disease vectors. Previous work on this project has contributed to progress toward achieving long-range goals 1 and 2. Current research will focus on a functional and active hobo -like element (Herves) in Anopheles gambiae. This element provides unprecedented opportunities to develop effective mosquito gene vectors and genetic drive agents as well as investigating the behavior of active transposable elements in populations of this important malaria vector. Our specific aims are to 1) determine the distribution and structure of Herves in An. gambiae and related species, 2) determine the characteristics of Herves movement within An. gambiae populations, 3) develop Herves into a mosquito gene vector. These aims will be accomplished by performing a combination of laboratory and field-based studies using molecular and population genetics tools.